Biological sampling has long been known as a mechanism for obtaining information concerning the physical condition of a subject. A wide variety of sampling techniques and analyses are known, the selection of which may depend on a number of factors, including the specific sample medium, the information sought, and the type of instrumentation to be used in performing the analysis.
As a general matter, most analytical techniques are customized to identify the presence and/or amount of a target substance or constituent in the biological sample. However, in some cases, the presence of certain substances within a sample may interfere with the ability of the analytical technique to obtain and provide such information. In cases where a conflict between sample constituents is identified, attempts are often made to design a sample preparation protocol that removes the problematic substance from the sample to the extent that complete and reliable identification or quantification of the target substance can be achieved.
For example, phospholipids have recently been identified as a potential cause of signal suppression or enhancement, during mass spectroscopic analysis of biological samples for certain target substances. Such suppression or enhancement impairs the accuracy and precision of the resulting data. The chemical configuration of phospholipids includes a hydrophilic polar head group and a hydrophobic tail, which can allow the phospholipid to interact with many different sample constituents. The ability of phospholipids to interact with a variety of substances may be an aspect of their potential to disrupt the assay. Thus, removing the phospholipids from the biological sample prior to mass spectrometric analysis, may allow greater accuracy and reliability of the analytical result obtained.
In some instances, however, removal of phospholipids from a biological sample may be desirable because the phospholipids are themselves the target constituent of interest. In such cases, isolation of the phospholipids from the sample may reduce or eliminate conflicts with certain other constituents and thus improve the reliability of the analysis for the phospholipids.
While removal or separation of phospholipids from a biological sample may be desirable for the above-recited reasons, it is to be noted that such removal should be selective in order to prevent target substances from also being removed along with the phospholipids. Further, when phospholipids are themselves the target substance, the non-selective removal thereof may in some aspects diminish the value of subsequent analytical results obtained.
As a result, methods and devices for separating phospholipids from biological samples, especially for selective separation of phospholipids from biological samples have been sought through research and development efforts.